Previously, various devices have been developed for the percutaneous delivery of medications into living organisms including syringes in which a liquid is delivered from a chamber using pressure asserted by a manual plunger through a needle inserted under the skin.
Additionally, it is well known in the art that the storage life of certain injectable substances such as glucagon, used to dissolve blood clots, is increased when the substance is stored in a powdered or lyophilized state, for example. These lyophilized substances (i.e., drugs or compounds) are presently used for injection of materials that would otherwise be unstable. Lyophilization, for example, is the rapid freezing of a material at a very low temperature followed by rapid dehydration by sublimation in a high vacuum. The resulting lyophilized compound is typically stored in a glass vial or cartridge which is closed by a cap, such as a rubber stopper or septum.
It is necessary to reconstitute the powdered or solid material, such as a lyophilized compound, prior to administration. This is accomplished by mixing the solid compound with a suitable diluent or liquid. Reconstitution typically involves the use of a syringe with a needle to withdraw the diluent from a separate vial and inject it into the vial containing the compound. The compound is then thoroughly mixed, typically by shaking the vial by hand, and a separate syringe with a needle withdraws the desired amount to be injected into the patient. Because two separate containers are used, the person reconstituting the compound must be certain to mix the correct amounts such that a proper concentration of the mixture results. When a syringe is used to mix the diluent and drug, the exact volume of diluent to drug ratio is difficult to obtain. Thus, precise concentration levels of administered drug may be compromised.
Moreover, because the diluent and compound are in separate, sterilized containers, the manual withdrawal of diluent via a syringe and reinjection of the same into the container containing the solid material such as a powdered or lyophilized drug may compromise sterility, and safety due to the use of a syringe.
Because of increased use of powdered compounds or lyophilized drugs, for example, it is desirable to provide both professional and non-professional personnel with a reconstituted drug delivery system. It is desirable to have a simple, reliable system that facilitates preparation and safe delivery of an accurate dosage of a reconstituted compound. In addition, it is desirable to provide a system that reconstitutes a lyophilized drug while maintaining sterility throughout the process. Also, it is desirable to provide improvements in the percutaneous delivery of medication generally, which provide for safe, effective administration by the user.
U.S. Pat. No. 6,364,865 discloses various different embodiments of medication delivery systems and transfer systems for forming a solution from constituents from a set of vials respectively containing a lyophilized compound and a diluent.
Sometimes a desired dose of a drug solution is larger than the amount corresponding to the drug contained in a single set of vials. In this case the total dose must be composed using lyophilized drug from two or more vial sets, the number of vial sets corresponding to the desired dose. This may, e.g., be done by sequentially applying a solvent liquid to each of the vials and retrieving the reconstituted drug to one common reservoir or syringe. When the drug of all of the vials has been reconstituted in this manner, the total dose may be administered to the person from the common reservoir or syringe. Reconstituting lyophilized drug from two or more vials in this manner is, however, relatively time consuming. Furthermore, there is a risk of contamination of the drug due to the number of times a free opening will be exposed to free air or dirt.
It is therefore desirable to provide a drug mixing device which facilitates mixing a dose using lyophilized drug from two or more vials, and which reduces the risk of contamination of the resulting drug.